This view of the twilight sky and Martian horizon taken by NASA's Curiosity Mars rover includes Earth as the brightest point of light in the night sky. Earth is a little left of center in the image, and our moon is just below Earth.

This frame from an animation from NASA's Mars rover Curiosity shows the rover drilling into rock target 'Cumberland.' The drilling was performed during the 279th Martian day, or sol, of the Curiosity's work on Mars (May 19, 2013).

This image from the Mars Hand Lens Imager on NASA's Mars rover Curiosity shows the patch of rock cleaned by the first use of the rover's Dust Removal Tool (DRT). The tool is a motorized, wire-bristle brush on the turret at the end of the rover's arm.

The two bodies in this portion of an evening-sky view by NASA's Mars rover Curiosity are Earth and Earth's moon. The rover's Mast Camera (Mastcam) imaged them in the twilight sky of Curiosity's 529th Martian day, or sol (Jan. 31, 2014).

These two images come from the HiRISE camera on NASA's Mars Reconnaissance Orbiter. Images of locations in Gale Crater taken from orbit around Mars reveal evidence of erosion in recent geological times and development of small scarps, or vertical surfaces

This mosaic of images from NASA's Curiosity shows geological members of the Yellowknife Bay formation, and the sites where Curiosity drilled into the lowest-lying member, called Sheepbed, at targets 'John Klein' and 'Cumberland'.

The rock 'Ithaca' is shown here with a rougher lower texture and smoother texture on top, and appears to be a piece of the local sedimentary bedrock protruding from the surrounding soil in Gale Crater as seen by NASA's Curiosity Mars rover.

Since landing on Mars in August 2012, NASA's Curiosity Mars rover has fired the laser on its Chemistry and Camera (ChemCam) instrument more than 100,000 times at rock and soil targets up to about 23 feet (7 meters) away.

The low ridge that appears as a dark band below the horizon in the center of this scene is a Martian outcrop called 'Cooperstown,' a possible site for contact inspection with tools on the robotic arm of NASA's Mars rover Curiosity.

This image of a U.S. penny on a calibration target was taken by the Mars Hand Lens Imager (MAHLI) aboard NASA's Curiosity rover in Gale Crater on Mars. At 14 micrometers per pixel, this is the highest-resolution image that MAHLI can acquire.

NASA's Mars rover Curiosity used a new technique, with added autonomy for the rover, in placement of the tool-bearing turret on its robotic arm. The technique is used to assess how close the instrument is to a soil or rock surface.

This mosaic of nine images taken at a location called 'Darwin,' inside Gale Crater, were taken by NASA's Mars rover Curiosity and shows detailed texture in a conglomerate rock bearing small pebbles and sand-size particles.

This image from NASA's Mars rover Curiosity provides a comparison for how big the moons of Mars appear to be, as seen from the surface of Mars, in relation to the size that Earth's moon appears to be when seen from the surface of Earth.

This view of the two moons of Mars comes from a set of images taken by NASA's Mars rover Curiosity as the larger moon, Phobos, passed in front of the smaller one, Deimos, from Curiosity's perspective, on Aug. 1, 2013.